Hello, could you describe more about your problem? it quite confused about what you telling
Does your problem started when you spilled coke on your computer (does it Laptop?) and you get replaced your Mainboard and it will shuts off after you turn on that laptop?
If that was your problem, could you tell who that replaced that Mainboard? if that was from Dell please bring it again to Dell as maybe it was still on warranty and if you try to fix it with yourself it will broke your laptop warranty.